String newContent = "New content\n";

        // Write initial content
        try (OutputStream out = file.openOutputStream(false)) {
            out.write(initialContent.getBytes("UTF-8"));
        }

        // Overwrite with new content
        try (OutputStream out = file.openOutputStream(false)) {
            out.write(newContent.getBytes("UTF-8"));
        }

    }

    // Test update method with InputStream
    public void test_update_withInputStream() throws Exception {
        writeTestFile("a,b => c\n");

        String newContent = "x,y => z\n";
        InputStream inputStream = new ByteArrayInputStream(newContent.getBytes(StandardCharsets.UTF_8));

        charMappingFile.update(inputStream);

        PagingList<CharMappingItem> result = charMappingFile.selectList(0, 10);